import {buildLineContent} from "../line/line_data.js"
import {lineNumberFor} from "../line/utils_line.js"
import {ie, ie_version} from "../util/browser.js"
import {elt, classTest} from "../util/dom.js"
import {signalLater} from "../util/operation_group.js"

// When an aspect of a line changes, a string is added to
// lineView.changes. This updates the relevant part of the line's
// DOM structure.
export function updateLineForChanges(cm, lineView, lineN, dims) {
    for (let j = 0; j < lineView.changes.length; j++) {
        let type = lineView.changes[j]
        if (type == "text") updateLineText(cm, lineView)
        else if (type == "gutter") updateLineGutter(cm, lineView, lineN, dims)
        else if (type == "class") updateLineClasses(cm, lineView)
        else if (type == "widget") updateLineWidgets(cm, lineView, dims)
    }
    lineView.changes = null
}

// Lines with gutter elements, widgets or a background class need to
// be wrapped, and have the extra elements added to the wrapper div
function ensureLineWrapped(lineView) {
    if (lineView.node == lineView.text) {
        lineView.node = elt("div", null, null, "position: relative")
        if (lineView.text.parentNode)
            lineView.text.parentNode.replaceChild(lineView.node, lineView.text)
        lineView.node.appendChild(lineView.text)
        if (ie && ie_version < 8) lineView.node.style.zIndex = 2
    }
    return lineView.node
}

function updateLineBackground(cm, lineView) {
    let cls = lineView.bgClass ? lineView.bgClass + " " + (lineView.line.bgClass || "") : lineView.line.bgClass
    if (cls) cls += " CodeMirror-linebackground"
    if (lineView.background) {
        if (cls) lineView.background.className = cls
        else {
            lineView.background.parentNode.removeChild(lineView.background);
            lineView.background = null
        }
    } else if (cls) {
        let wrap = ensureLineWrapped(lineView)
        lineView.background = wrap.insertBefore(elt("div", null, cls), wrap.firstChild)
        cm.display.input.setUneditable(lineView.background)
    }
}

// Wrapper around buildLineContent which will reuse the structure
// in display.externalMeasured when possible.
function getLineContent(cm, lineView) {
    let ext = cm.display.externalMeasured
    if (ext && ext.line == lineView.line) {
        cm.display.externalMeasured = null
        lineView.measure = ext.measure
        return ext.built
    }
    return buildLineContent(cm, lineView)
}

// Redraw the line's text. Interacts with the background and text
// classes because the mode may output tokens that influence these
// classes.
function updateLineText(cm, lineView) {
    let cls = lineView.text.className
    let built = getLineContent(cm, lineView)
    if (lineView.text == lineView.node) lineView.node = built.pre
    lineView.text.parentNode.replaceChild(built.pre, lineView.text)
    lineView.text = built.pre
    if (built.bgClass != lineView.bgClass || built.textClass != lineView.textClass) {
        lineView.bgClass = built.bgClass
        lineView.textClass = built.textClass
        updateLineClasses(cm, lineView)
    } else if (cls) {
        lineView.text.className = cls
    }
}

function updateLineClasses(cm, lineView) {
    updateLineBackground(cm, lineView)
    if (lineView.line.wrapClass)
        ensureLineWrapped(lineView).className = lineView.line.wrapClass
    else if (lineView.node != lineView.text)
        lineView.node.className = ""
    let textClass = lineView.textClass ? lineView.textClass + " " + (lineView.line.textClass || "") : lineView.line.textClass
    lineView.text.className = textClass || ""
}

function updateLineGutter(cm, lineView, lineN, dims) {
    if (lineView.gutter) {
        lineView.node.removeChild(lineView.gutter)
        lineView.gutter = null
    }
    if (lineView.gutterBackground) {
        lineView.node.removeChild(lineView.gutterBackground)
        lineView.gutterBackground = null
    }
    if (lineView.line.gutterClass) {
        let wrap = ensureLineWrapped(lineView)
        lineView.gutterBackground = elt("div", null, "CodeMirror-gutter-background " + lineView.line.gutterClass,
            `left: ${cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth}px; width: ${dims.gutterTotalWidth}px`)
        cm.display.input.setUneditable(lineView.gutterBackground)
        wrap.insertBefore(lineView.gutterBackground, lineView.text)
    }
    let markers = lineView.line.gutterMarkers
    if (cm.options.lineNumbers || markers) {
        let wrap = ensureLineWrapped(lineView)
        let gutterWrap = lineView.gutter = elt("div", null, "CodeMirror-gutter-wrapper", `left: ${cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth}px`)
        cm.display.input.setUneditable(gutterWrap)
        wrap.insertBefore(gutterWrap, lineView.text)
        if (lineView.line.gutterClass)
            gutterWrap.className += " " + lineView.line.gutterClass
        if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))
            lineView.lineNumber = gutterWrap.appendChild(
                elt("div", lineNumberFor(cm.options, lineN),
                    "CodeMirror-linenumber CodeMirror-gutter-elt",
                    `left: ${dims.gutterLeft["CodeMirror-linenumbers"]}px; width: ${cm.display.lineNumInnerWidth}px`))
        if (markers) for (let k = 0; k < cm.display.gutterSpecs.length; ++k) {
            let id = cm.display.gutterSpecs[k].className, found = markers.hasOwnProperty(id) && markers[id]
            if (found)
                gutterWrap.appendChild(elt("div", [found], "CodeMirror-gutter-elt",
                    `left: ${dims.gutterLeft[id]}px; width: ${dims.gutterWidth[id]}px`))
        }
    }
}

function updateLineWidgets(cm, lineView, dims) {
    if (lineView.alignable) lineView.alignable = null
    let isWidget = classTest("CodeMirror-linewidget")
    for (let node = lineView.node.firstChild, next; node; node = next) {
        next = node.nextSibling
        if (isWidget.test(node.className)) lineView.node.removeChild(node)
    }
    insertLineWidgets(cm, lineView, dims)
}

// Build a line's DOM representation from scratch
export function buildLineElement(cm, lineView, lineN, dims) {
    let built = getLineContent(cm, lineView)
    lineView.text = lineView.node = built.pre
    if (built.bgClass) lineView.bgClass = built.bgClass
    if (built.textClass) lineView.textClass = built.textClass

    updateLineClasses(cm, lineView)
    updateLineGutter(cm, lineView, lineN, dims)
    insertLineWidgets(cm, lineView, dims)
    return lineView.node
}

// A lineView may contain multiple logical lines (when merged by
// collapsed spans). The widgets for all of them need to be drawn.
function insertLineWidgets(cm, lineView, dims) {
    insertLineWidgetsFor(cm, lineView.line, lineView, dims, true)
    if (lineView.rest) for (let i = 0; i < lineView.rest.length; i++)
        insertLineWidgetsFor(cm, lineView.rest[i], lineView, dims, false)
}

function insertLineWidgetsFor(cm, line, lineView, dims, allowAbove) {
    if (!line.widgets) return
    let wrap = ensureLineWrapped(lineView)
    for (let i = 0, ws = line.widgets; i < ws.length; ++i) {
        let widget = ws[i],
            node = elt("div", [widget.node], "CodeMirror-linewidget" + (widget.className ? " " + widget.className : ""))
        if (!widget.handleMouseEvents) node.setAttribute("cm-ignore-events", "true")
        positionLineWidget(widget, node, lineView, dims)
        cm.display.input.setUneditable(node)
        if (allowAbove && widget.above)
            wrap.insertBefore(node, lineView.gutter || lineView.text)
        else
            wrap.appendChild(node)
        signalLater(widget, "redraw")
    }
}

function positionLineWidget(widget, node, lineView, dims) {
    if (widget.noHScroll) {
        ;(lineView.alignable || (lineView.alignable = [])).push(node)
        let width = dims.wrapperWidth
        node.style.left = dims.fixedPos + "px"
        if (!widget.coverGutter) {
            width -= dims.gutterTotalWidth
            node.style.paddingLeft = dims.gutterTotalWidth + "px"
        }
        node.style.width = width + "px"
    }
    if (widget.coverGutter) {
        node.style.zIndex = 5
        node.style.position = "relative"
        if (!widget.noHScroll) node.style.marginLeft = -dims.gutterTotalWidth + "px"
    }
}
